Wheeler's body was discovered New Year's Eve as it was being dropped from a Newark, Del., city Dumpster into the Cherry Island landfill in Wilmington. An autopsy found that he was a victim of homicide, but police are not releasing any details of the medical report.

John "Jack" Wheeler was known as a man of honor: a West Point graduate, a Vietnam veteran, and the man who was the driving force behind financing the construction of the Vietnam Veterans Memorial.

He served three presidents -- Ronald Reagan, George H.W. Bush and George W. Bush, for whom he was a special assistant to the Secretary of the Air Force. He moved easily among Washington's elite, working most recently as a military consultant.

But the circumstances of his death are a mystery. Police said today they don't know where he was killed, why he was killed, or who may have killed him.

Investigators were back at the landfill today, scouring for leads.

"We have no suspects at this time," Lt. Mark Farrall of the Newark police told ABC News. "What's important now is to establish the location of the crime."

Farrall said that Wheeler, who who has homes in Washington, D.C., and in New Castle, Del., was scheduled to take a train from Washington to Wilmington on Dec. 28.

But at this point, he said, police have no information about Wheeler's whereabouts that week.

"His family was travelling, so no one reported him missing," Farrall said.

Wheeler reportedly was in a running dispute with a neighbor who was building a house across the street from his home in New Castle. Wheeler filed suit to halt the construction, which partially blocked his view of the river.

"The home construction dispute is one aspect we are considering," Farrall said. "But it is just one aspect, it's not the focus of our investigation."

Wheeler's death has saddened many of his close friends, including former CIA Director Jim Woolsey and author James Fallows.

Fallows wrote a tribute to Wheeler in the Atlantic Magazine online, saying, "I feel terrible for his family and hope they will eventually find comfort in knowing how many important things he achieved."